In semiconductor chips comprising complementary metal oxide on semiconductor (CMOS) integrated circuits, circuit contacts and interconnects may be fabricated from various metals, such as lead (Pb) or gold (Au). High volume production of semiconductor chips containing these metals may result in environmental pollution, as such metals may be inherently environmentally unfriendly, and may be hazardous to the environment if discarded products containing the semiconductor chips are not disposed of properly. The use of metal in semiconductor chips may also constrain fabrication process conditions, for example, limiting maximum process temperatures and presenting problems with tool cross-contamination.